May 2023 Spider Of The Month

The spider of the month (SOTM) is this beetle-mimic jumping spider (Pachyballus sp.; Salticidae), photographed by Robert Wienand in Sabie Park near the Kruger National Park in Mpumalanga.

Regarding this find, Robert said:

“Being a fairly regular visitor to Sabie Park has made this private reserve one of my favourite places for finding jumping spiders. On our visit there end of March it was much the same as before, with jumping spiders all over. An afternoon outing to the picnic area overlooking the Sabie River proved to be fruitful when my eye caught movement on the braai grid close to where we were seated. Fortunately, I have had previous encounters with beetle-mimic jumping spiders and could see this was not just another beetle. It was, however, only my 3rd sighting of one and another highlight. Hopefully one day I can get the necessary video gear to share with everyone what they look like when moving. Wonderful little spiders.”

These spiders are supposed Batesian mimics of beetles, which means a “harmless” species mimicking a “not so harmless” species, or a palatable species mimicking an unpalatable species. Not much else in known about their mimicry, and which beetles they mimic in order to escape which predator, but these predators might include araneophagous spiders who hunt other spiders, and who would therefore avoid beetles. They have been observed to even sometimes fool the smartest spiders in the world, the “dandy” jumping spiders (Portia spp.). For example, Harland and Jackson (2001, 2002) observed that while only half of Portia fimbriata were fooled by Pachyballus cordiformis’s appearance and did not classify them as prey, the other half who did classify them as prey mostly did not engage in cryptic stalking, which is how Portia spp. stalk other jumping spiders. This means that while they see them as prey about 50% of the time, they don’t see them as another jumping spider about 85% of the time, possibly because their anterior median eyes are so closely situated on a wide face.

Pachyballus originates from “pachy”, meaning “thick” (think pachyderms, or thick-skinned animals, like elephants, rhinos, and hippos) and ballus, which probably originates from the Greek “ballizo”, meaning to jump or dance (think ballerina). Ballus is a different genus of jumping spiders.  

There are only nine recorded species in the world; four of which were recently described by Wesołowska, Azarkina and Wiśniewski in 2020. Eight of these species can be found only in Africa, and only one species (P. gambeyi) found on the French island of New Caledonia east of Australia.

This is Robert’s fifth SOTM from 40 nominations. This makes him our very first five-time winner! He received 181 of the 476 votes. Congratulations, Robert!